fix Issue 11216 - Make synchronized statement `nothrow`

- mark _d_monitorenter/exit as nothrow
Fix unconvertible comment
Fix shadowing
Do not rely on implicit conversion from integer to bool
Do not use reserved identifier '__dollar' for a variable name
Do not name a variable 'pure'
Fix Issue 10311 - GDB prints wrong value for variable updated from closure
Merge pull request #4074 from tramker/bug10311

Fix Issue 10311 - GDB prints wrong value for variable updated from closure
Merge pull request #4115 from MartinNowak/fix11216

fix Issue 11216 - Make synchronized statement `nothrow`
Merge pull request #4116 from yebblies/intbool

[DDMD] Do not rely on implicit conversion from integer to bool
Merge pull request #4120 from yebblies/gagshadow

[DDMD] Fix shadowing
Merge pull request #4119 from yebblies/commentxx

[DDMD] Fix unconvertible comment
Merge pull request #4117 from yebblies/dollar

[DDMD] Do not use reserved identifier '__dollar' for a variable name
Merge pull request #4118 from yebblies/purevar

[DDMD] Do not name a variable 'pure'
Explicitly cast AA value to void*