Add accessor for included pty instance

[laeubi]

Currently if I get passed a Process from by a method call I can check it for the Spawner and can already call special methods like hangup(). But there is no way to get access the the PTY used to create the Spawner so for example one can't call PTY#setTerminalSize or query any other properties.

This now adds a new method pty() that returns this instance for further investigation and actions.

See

• Add support for launching Eclipse Process in a system terminal session eclipse-platform/eclipse.platform#1762 (comment)

[laeubi]

The cleancheck fails with

[ERROR] Changes not staged for commit:
[ERROR] 	modified:    core/org.eclipse.cdt.core.native/about.properties

but I can't see how this relates to my commit...

[github-actions]

Test Results

   602 files   -    34     602 suites   - 34   13m 21s ⏱️ - 23m 10s
10 222 tests  - 1 217  10 198 ✅  - 1 096  24 💤  - 120  0 ❌ ±0 
10 260 runs   - 1 194  10 236 ✅  - 1 075  24 💤  - 118  0 ❌ ±0 

Results for commit 8fa4a3e. ± Comparison against base commit 52456bc.

This pull request removes 1217 tests.

org.eclipse.cdt.debug.gdbjtag.core.tests.jtagdevice.GDBJtagDeviceContributionTest ‑ testGdbJtagDeviceContribution
org.eclipse.cdt.debug.gdbjtag.core.tests.launch.GDBJtagLaunchTest ‑ testGdbJtagLaunch[gdb]
org.eclipse.cdt.debug.gdbjtag.core.tests.launch.GDBJtagLaunchTest ‑ testGdbJtagLaunch[gdbserver]
org.eclipse.cdt.tests.dsf.gdb.tests.CommandLineArgsTest ‑ testSettingArgumentsWithQuotes[gdb]
org.eclipse.cdt.tests.dsf.gdb.tests.CommandLineArgsTest ‑ testSettingArgumentsWithQuotes[gdbserver]
org.eclipse.cdt.tests.dsf.gdb.tests.CommandLineArgsTest ‑ testSettingArgumentsWithSpecialSymbols[gdb]
org.eclipse.cdt.tests.dsf.gdb.tests.CommandLineArgsTest ‑ testSettingArgumentsWithSpecialSymbols[gdbserver]
org.eclipse.cdt.tests.dsf.gdb.tests.CommandLineArgsTest ‑ testSettingArgumentsWithSymbols[gdb]
org.eclipse.cdt.tests.dsf.gdb.tests.CommandLineArgsTest ‑ testSettingArgumentsWithSymbols[gdbserver]
org.eclipse.cdt.tests.dsf.gdb.tests.CommandLineArgsTest ‑ testSettingArgumentsWithTabs[gdb]
…