QuickJS: fixed alg may be used uninitialized in SubtleCrypto.import().

[xeioex]

Collecting coverage for WebCrypto module:

make clean; ./configure  --cc-opt='-fprofile-arcs -ftest-coverage -O0 -g -I/path/to/quickjs' --ld-opt='-L/path/to/quickjs -lgcov' && make njs
test/test262 --binary='build/njs -n QuickJS -m' ./test/webcrypto/

gcov -o build/external/ -b -a external/qjs_webcrypto_module.c
Lines executed:70.19% of 2221
Branches executed:95.50% of 1244
Taken at least once:64.07% of 1244
Calls executed:75.27% of 1100
Creating 'qjs_webcrypto_module.c.gcov'
...

qjs_webcrypto_module.c.gcov # contains line by line coverage in text form

File 'external/qjs_webcrypto_module.c'
-Lines executed:67.90% of 2221
-Branches executed:94.70% of 1246
-Taken at least once:61.32% of 1246
-Calls executed:72.73% of 1100
+Lines executed:70.19% of 2221
+Branches executed:95.50% of 1244
+Taken at least once:64.07% of 1244
+Calls executed:75.27% of 1100

[VadimZhestikov]

Looks good