feat: add multi-arch CI matrix with nan-tagging toggle and 32-bit test suite

Add Travis CI configuration to build and test Wren on both Linux and macOS, for both 32-bit and 64-bit architectures, with and without WREN_NAN_TAGGING defined. Introduce `ci_32` and `ci_64` make targets that build debug/release and C/C++ variants, then run the test suite against each binary using a suffix parameter. Update `util/test.py` with argparse to accept `--suffix` and `suite` arguments, increase test timeout from 2 to 5 seconds, and fix handle leak in `test/api/slots.c` by moving `wrenReleaseHandle` after the conditional block. Replace `fpclassify`/`signbit` checks for infinity/nan in `wrenNumToString` to avoid GCC overflow warnings on 32-bit, double-cast `double` to `uint32_t` in `num_bitwiseNot` to prevent undefined behavior, and relax floating-point comparisons in `test/core/number/sin.wren` and `cos.wren` to use absolute tolerance. Comment out hex literals larger than `0x1000000` in `example/syntax.wren` since they exceed 32-bit range, and bump libuv from v1.8.0 to v1.10.0 for 32-bit build fixes.

test/core/number/cos.wren

@@ -3,4 +3,4 @@ System.print(Num.pi.cos)        // expect: -1
 System.print((2 * Num.pi).cos)  // expect: 1
 
 // this should of course be 0, but it's not that precise
-System.print((Num.pi / 2).cos)  // expect: 6.1232339957368e-17
+System.print((Num.pi / 2).cos.abs < 1.0e-16) // expect: true

test/core/number/sin.wren

@@ -2,5 +2,5 @@ System.print(0.sin)             // expect: 0
 System.print((Num.pi / 2).sin)  // expect: 1
 
 // these should of course be 0, but it's not that precise
-System.print(Num.pi.sin)        // expect: 1.2246467991474e-16
-System.print((2 * Num.pi).sin)  // expect: -2.4492935982947e-16
+System.print(Num.pi.sin.abs < 1.0e-15)        // expect: true
+System.print((2 * Num.pi).sin.abs < 1.0e-15)  // expect: true