Fix handling of HaltCompilerStatement

[TysonAndre]

Make it easier to calculate __COMPILER_HALT_OFFSET__ and make properties other than data non-null.
Combine all tokens after halt compiler statement into an InlineHtml token that goes into HaltCompilerStatement->data if there are bytes.
Related to #381

[TysonAndre]

This is ready for review. The ParserInvariantTest asserts that the tokens combine into the original file for the test cases of __halt_compiler(). The subsequent commit is just another test case.

[TysonAndre]

One last change: A real InlineHtml node would have no leading whitespace/comments, so make fullStart = start.

• In places that aren't HaltCompilerStatement (EchoStatement), it's always at the start of a file or after ?>/?>\n, and the newline is part of the close tag token instead of the InlineHtml token

[TysonAndre]

The reasoning in updating the tests I'd added in the previous PR is that HaltCompiler should halt the compiler and not parse any more statements, so I'd treat the snippet like __halt_compiler[();]::foo(); with inline html of ::foo();\n
(this token can't be used in other statements/expressions and is a syntax error)

<?php
// invalid
__halt_compiler::foo();

The MissingToken in the original tree were due to token_get_all() returning at most 3 tokens after T_HALT_COMPILER then returning T_INLINE_HTML for the rest