[LANG-1809] fix typo in method name geStringtVarStringArgs in MethodFixtures

[IcoreE]

The MethodFixtures class contains a method with a typo in its name (geStringtVarStringArgs) and a corresponding static helper method that references this misspelled name, which impacts code readability and maintainability: 

1. Misspelled method name

// Incorrect: "geStringt" (extra 't' after 'String')
public String geStringtVarStringArgs(final String... strings) {
    return "XYZ";
}

2. Dependent static helper method
   The static method getMethodForGetStringVarStringArgs() references the misspelled method name via reflection:

static Method getMethodForGetStringVarStringArgs() throws NoSuchMethodException, SecurityException {
    // References the typo'd method name "geStringtVarStringArgs"
    return getDeclaredMethod("geStringtVarStringArgs", String[].class);
}  

[garydgregory]

@IcoreE
Please refrain from creating Jira tickets for minor changes.

[IcoreE]

Okay, I'll be more careful with this from now on. Thanks for reminding me. @garydgregory

[garydgregory]

Jira is https://issues.apache.org/jira/browse/LANG-1809