[PLAT-13280] More robust crosstalk API, and also a permissive proxy class

[kstenerud]

Goal

Make the crosstalk API more robust, with stable and predictable return error values that help identify potential problems.

Also added a permissive proxy that gracefully degrades to a no-op when an unknown method or property is called.

These two classes can help make cross-library calling less painful by removing the need to put if statements around everything in order to avoid a crash or bad data.

Design

The code has been updated so that the CrossTalk API and also the client-side implementation in the unit tests can be used as templates for how to implement either in another library. This will cause code duplication, but I think it's preferable to causing yet another library dependency.

Testing

Added unit test to cover more edge cases.

[github-actions]

BugsnagPerformance.framework binary size increased by 4,296 bytes from 519,872 to 524,168

    FILE SIZE        VM SIZE    
 --------------  -------------- 
  +1.7% +2.05Ki  +1.7% +2.05Ki    String Table
  +2.0% +2.05Ki  +2.0% +2.05Ki    Symbol Table
  +1.7% +1.93Ki  +1.7% +1.93Ki    __TEXT,__text
  +3.7%    +680  +3.7%    +680    __DATA,__objc_const
  +2.3%    +288  +2.3%    +288    __TEXT,__objc_stubs
  +2.3%    +176  +2.3%    +176    __TEXT,__cstring
  +1.5%    +176  +1.5%    +176    __TEXT,__gcc_except_tab
  +1.1%    +166  +1.1%    +166    __TEXT,__objc_methname
  +0.7%     +86  +0.7%     +86    [10 Others]
  +4.5%     +80  +4.5%     +80    __DATA,__objc_data
  +1.6%     +80  +1.6%     +80    __TEXT,__unwind_info
  +2.0%     +64  +2.0%     +64    __DATA,__objc_selrefs
  +6.8%     +41  +6.8%     +41    __TEXT,__objc_classname
  +0.9%     +32  +0.9%     +32    Lazy Binding Info
  +0.4%     +32  +0.4%     +32    __DATA_CONST,__cfstring
  +2.0%     +24  +2.0%     +24    Function Start Addresses
  +2.3%     +24  +2.3%     +24    Rebase Info
  -1.8%     -40  -1.8%     -40    [__DATA_CONST]
 -12.4%    -860 -12.6%    -860    [__DATA]
  -6.3% -2.86Ki  -6.3% -2.86Ki    [__TEXT]
  [ = ]       0 -97.2% -4.20Ki    [__LINKEDIT]
  +0.8% +4.20Ki  [ = ]       0    TOTAL

Generated by 🚫 Danger