RFR: 8282008: Incorrect handling of quoted arguments in ProcessBuilder

[Olga Mikhaltsova]

This fix made equal processing of strings such as ""C:\\Program Files\\Git\\"" before and after JDK-8250568.

For example, it's needed to execute the following command on Windows:
`C:\Windows\SysWOW64\WScript.exe "MyVB.vbs" "C:\Program Files\Git" "Test"`
it's equal to:
`new ProcessBuilder("C:\\Windows\\SysWOW64\\WScript.exe", "MyVB.vbs", ""C:\\Program Files\\Git\\"", "Test").start();`

While processing, the 3rd argument ""C:\\Program Files\\Git\\"" treated as unquoted due to the condition added in JDK-8250568.

    private static String unQuote(String str) {
    .. 
       if (str.endsWith("\\"")) {
            return str;    // not properly quoted, treat as unquoted
        }
    ..
    }


that leads to the additional surrounding by quotes in ProcessImpl::createCommandLine(..) because needsEscaping(..) returns true due to the space inside the string argument.
As a result the native function CreateProcessW (src/java.base/windows/native/libjava/ProcessImpl_md.c) gets the incorrectly quoted argument: 

pcmd = C:\Windows\SysWOW64\WScript.exe MyVB.vbs ""C:\Program Files\Git"" Test
(jdk.lang.Process.allowAmbiguousCommands = true)
pcmd = "C:\Windows\SysWOW64\WScript.exe" MyVB.vbs ""C:\Program Files\Git\\"" Test
(jdk.lang.Process.allowAmbiguousCommands = false)


Obviously, a string ending with "\\"" must not be started with """ to treat as unquoted overwise it’s should be treated as properly quoted.

-------------

Commit messages:
 - 8282008: Incorrect handling of quoted arguments in ProcessBuilder

Changes: https://git.openjdk.java.net/jdk/pull/7504/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7504&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8282008
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7504.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7504/head:pull/7504

PR: https://git.openjdk.java.net/jdk/pull/7504