[dmd-internals] Patches for regression+wrong code + ICE bugs

[Don Clugston]

All except rsinfu's patch for 4217 are very simple.

4825 Regression(1.057, 2.040) "Error: non-constant expression" with -inline
2943 Struct copying in presence of alias member this only copies alias
this member
     also fixes 4641 Associative arrays of structs with alias this broken
4217 Function overloads are not distinguished when instantiating templates

4949 ICE on invalid static if using value of 'this'
4873 Assertion failure: '0' on line 1483 in file 'expression.c'

This unimportant but trivial one is from dstress. Note: there's an
if() goto Lbaddim; in the patch which isn't not marked with +.
4623 Non-integer type allowed as static array size