parser: can't handle multiline comments that do not close

[tpdenk]

Describe the bug
Fuzzing.

To Reproduce
Input:

/*..*...........

Hex:

2F 2A 03 09 2A 00 00 00 00 00 00 00 00 00 00 00

Panic:

panic: runtime error: index out of range [5] with length 5

goroutine 1 [running]:
runtime/debug.Stack(0xc0001fe2b8, 0xc00001a1c0, 0x33)
	/usr/local/go/src/runtime/debug/stack.go:24 +0xfd
git.fuzzbuzz.io/fuzz.(*F).Close(0xc00020e000)
	git.fuzzbuzz.io/fuzz/f_obj.go:609 +0x7b2
panic(0x779180, 0xc0001fe2b8)
	runtime/panic.go:965 +0x1b9
github.com/xqueries/xdb/internal/parser/scanner.(*ruleBasedScanner).ConsumeRune(0xc0002067e0)
	/src/internal/parser/scanner/rule_based_scanner.go:258 +0xe7
github.com/xqueries/xdb/internal/parser/scanner.(*ruleBasedScanner).drainComment.func2(0xc0002067e0, 0x0)
	/src/internal/parser/scanner/rule_based_scanner.go:178 +0x34a
github.com/xqueries/xdb/internal/parser/scanner.(*ruleBasedScanner).drainComment(0xc0002067e0, 0x756980)
	/src/internal/parser/scanner/rule_based_scanner.go:198 +0x1ee
github.com/xqueries/xdb/internal/parser/scanner.(*ruleBasedScanner).drainWhitespacesAndComments(0xc0002067e0)
	/src/internal/parser/scanner/rule_based_scanner.go:119 +0x87
github.com/xqueries/xdb/internal/parser/scanner.(*ruleBasedScanner).computeNext(0xc0002067e0, 0xa, 0xa)
	/src/internal/parser/scanner/rule_based_scanner.go:92 +0x47
github.com/xqueries/xdb/internal/parser/scanner.(*ruleBasedScanner).Peek(0xc0002067e0, 0x0, 0x0)
	/src/internal/parser/scanner/rule_based_scanner.go:74 +0xb2
github.com/xqueries/xdb/internal/parser.(*simpleParser).Next(0xc00004fec0, 0x5, 0x7ed8e0, 0xc00004fec0, 0x0, 0x0)
	/src/internal/parser/simple_parser.go:28 +0x4f
github.com/xqueries/xdb.Fuzz(0xc0001f8a76, 0x5, 0x6, 0x0)
	/src/xdb_fuzz.go:35 +0x115
github.com/xqueries/xdb.FuzzGoFuzzFuzz(0xc00020e000)
	/src/fuzzbuzz_autogen.go:7 +0x8c
github.com/xqueries/xdb/fuzzing/fuzzbuzzauto.FuzzFunction0(...)
	/src/fuzzing/fuzzbuzzauto/fuzz.go:8
github.com/xqueries/xdb/fuzzing/fuzzbuzzauto.FuzzFunction0_FuzzWrapper(0xb5196858a4ba43c3, 0x73cac0, 0xc0001f5140, 0x0)
	github.com/xqueries/xdb/fuzzing/fuzzbuzzauto/fuzzwrappers.go:12 +0x91
git.fuzzbuzz.io/fuzz/endpoint.(*StandardFuzzEndpoint).StartMain(0xc000119e28)
	git.fuzzbuzz.io/fuzz/endpoint/endpoint.go:124 +0x422
base-dep.Main(0x9eb938, 0x0, 0x0, 0xc00001cb30, 0x4, 0x4, 0xc000010050, 0x1, 0x1)
	base-dep/main.go:43 +0x329
main.main()
	github.com/xqueries/xdb/fuzzing/fuzzbuzzauto/go.fuzz.main/main.go:18 +0xc5