Fix Windows batch file syntax error in escapePipes subroutine

The original code used 'if "\!char\!"=="^""' to check for double quote
characters, but this syntax doesn't work correctly with delayed expansion
enabled in Windows batch files, causing "The syntax of the command is
incorrect" errors.

The fix introduces an intermediate variable 'isQuote' and uses the proper
batch file syntax 'if "\!char\!"==""""' (four consecutive quotes) to
check for a double quote character. This is the standard way to represent
a literal quote in batch file comparisons.

This resolves the IT failures on Windows for tests that use jvm.config
files, including:
- MavenITmng8598JvmConfigSubstitutionTest
- MavenITmng6255FixConcatLines
- MavenITmng6223FindBasedir

Author: gnodet

apache-maven/src/assembly/maven/bin/mvn.cmd

@@ -263,4 +263,45 @@ if exist "%USERPROFILE%\mavenrc_post.cmd" call "%USERPROFILE%\mavenrc_post.cmd"
 @REM pause the script if MAVEN_BATCH_PAUSE is set to 'on'
 if "%MAVEN_BATCH_PAUSE%"=="on" pause
 
-exit /b %ERROR_CODE%
+exit /b %ERROR_CODE%
+
+rem Subroutine to escape pipe symbols that are not within quotes
+:escapePipes
+setlocal EnableDelayedExpansion
+set "input=%~1"
+set "output="
+set "inQuotes=0"
+set "i=0"
+
+:escapeLoop
+set "char=!input:~%i%,1!"
+if "!char!"=="" goto escapeEnd
+
+rem Check if character is a double quote using string comparison
+set "isQuote=0"
+if "!char!"=="""" set "isQuote=1"
+
+if "!isQuote!"=="1" (
+    if "!inQuotes!"=="0" (
+        set "inQuotes=1"
+    ) else (
+        set "inQuotes=0"
+    )
+    set "output=!output!!char!"
+) else if "!char!"=="|" (
+    if "!inQuotes!"=="0" (
+        rem Escape pipe with 7 carets to survive endlocal and command line parsing
+        set "output=!output!^^^^^^^|"
+    ) else (
+        set "output=!output!!char!"
+    )
+) else (
+    set "output=!output!!char!"
+)
+
+set /a "i+=1"
+goto escapeLoop
+
+:escapeEnd
+endlocal & set "%~2=%output%"
+goto :eof