Fix parser.t tests 14 and 15: handle backslash-c without character and dollar at end of string

[fglock]

Summary

Fixed two failing parser tests in perl5_t/t/comp/parser.t:

Test 14: backslash-c without character

• Problem: Missing control character after backslash-c should generate an error
• Solution: Added proper error handling in StringDoubleQuoted.handleControlCharacter() and StringSegmentParser.handleControlCharacter()
• Result: Now throws the correct error message when control character is missing

Test 15: dollar at end of string

• Problem: dollar at the end of double-quoted string should generate Final dollar should be backslash-dollar or dollarname error
• Solution: Added check for empty identifier in parseSimpleVariableInterpolation() when dollar sigil is at EOF
• Result: Now generates the exact expected error message

Changes Made

1. StringDoubleQuoted.java:

   • Added PerlCompilerException import
   • Modified handleControlCharacter() to throw proper error when character is missing

2. StringSegmentParser.java:

   • Modified handleControlCharacter() to throw proper error when character is missing
   • Added targeted EOF check in shouldInterpolateVariable() for dollar sigil in double-quoted strings
   • Added check for empty identifier in parseSimpleVariableInterpolation() to handle dollar at end of string
   • Added getter method for originalStringContent

Test Results

• Test 14: backslash-c string - PASSED
• Test 15: dollar at end of string - PASSED
• make build: HEALTHY
• All other tests: PASSING (no regressions)

Verification

Both tests now pass with the exact expected error messages:

• Test 14: Handles missing control character after backslash-c
• Test 15: Generates Final dollar should be backslash-dollar or dollarname for dollar at end of string

The fixes are minimal and targeted, only affecting the specific error cases without breaking existing functionality.